DE-102025137980-A1 - PHASE-CHANGING MATERIAL DEVICE AND METHOD FOR ITS FORMATION

DE102025137980A1DE 102025137980 A1DE102025137980 A1DE 102025137980A1DE-102025137980-A1

Abstract

A phase-change storage device can be provided by: forming a bottom electrode, a layer of dielectric material, and a via opening that extends through the layer of dielectric material such that a top segment of the bottom electrode is exposed below the via opening; forming a tubular dielectric spacer in a peripheral region of the via opening; depositing a continuous layer stack comprising a heater lining layer, a phase-change material layer including a phase-change material, and a material layer for the top electrode above the layer of dielectric material and the tubular dielectric spacer; and structuring the continuous layer stack into a layer stack comprising a heater lining, a phase-change material section, and a top electrode.

Inventors

Chang-Chih Huang
Chih-Ren Hsieh
Kuo-Pin Chang
Kuo-Ching Huang

Assignees

TAIWAN SEMICONDUCTOR MANUFACTURING CO., LTD.

Dates

Publication Date: 20260513
Application Date: 20250919
Priority Date: 20250211

Claims (20)

A method for forming a device structure comprising: Forming a bottom electrode, a layer of dielectric material, and a via opening extending through the layer of dielectric material such that a top segment of the bottom electrode is exposed below the via opening; Forming a tubular dielectric spacer in a peripheral region of the via opening such that a central section of the top segment is exposed below a void laterally surrounded by the tubular dielectric spacer; Depositing a continuous stack of layers comprising a heater lining layer, a phase-change material layer comprising a phase-change material, and a material layer for the top electrode over the layer of dielectric material and the tubular dielectric spacer; and Structuring the continuous stack of layers into a stack comprising a heater lining, a phase-change material section, and a top electrode.
Procedure according to Claim 1 , wherein the heating lining layer comprises a vertically extending section deposited in a void within the tubular dielectric spacer and a horizontally extending section deposited above a top surface of the layer of dielectric material.
Procedure according to Claim 1 or 2 , wherein a vertically extending seam is formed in the middle of the vertically extending section of the heating lining layer.
Procedure according to Claim 2 or 3 , wherein the phase-change material layer comprises a vertically extending section having a cylindrical side wall that contacts an inner cylindrical side wall of the tubular dielectric spacer.
Procedure according to one of the Claims 1 until 4 , further comprising: depositing a layer of dielectric spacer material in the edge region of the via hole and over the layer of dielectric material; and anisotropic etching of the layer of dielectric spacer material, wherein a remaining vertically extending section of the layer of dielectric spacer material filling the edge region of the via hole forms the tubular dielectric spacer.
Procedure according to one of the Claims 1 until 5 , wherein: the heating lining layer is deposited on the middle section of the top-side segment of the lower electrode; and the phase-change material layer is deposited on a planar horizontal surface segment of the heating lining layer that lies above a horizontal plane having a top-side layer of dielectric material.
Procedure according to one of the Claims 1 until 6 , wherein: the heating lining layer, after deposition of the heating lining layer, comprises a planar horizontal surface segment that lies above the layer of dielectric material, and further comprises an annular convex surface segment that borders a circumferential edge of an opening in the planar horizontal surface segment and lies above the via opening; and the phase change material layer is deposited directly onto the annular convex surface segment.
Procedure according to Claim 7 , wherein: the heating lining layer is deposited by a conformal deposition process; a maximum width of the void is less than half the thickness of the heating lining layer; and a vertically extending seam is formed in the center of the void, which is filled with a vertically extending section of the heating lining layer.
Procedure according to Claim 7 , wherein: the heater lining layer is deposited by a conformal deposition process; a maximum width of the vacancy is greater than half the thickness of the heater lining layer; an unfilled portion of the vacancy exists within a volume of the via opening after the formation of the heater lining layer; and a vertically extending portion of the phase change material layer is deposited within the unfilled portion of the vacancy.
Procedure according to one of the Claims 1 until 9 , furthermore comprising the formation of at least one side wall lining by depositing and structuring a side wall lining material, wherein the at least one side wall a lining is formed on at least one side wall of the layer stack, wherein the at least one side wall lining comprises a material with an electrical conductivity that is higher than an electrical conductivity of an amorphous phase of the phase change material.
A method for forming a device structure comprising: Forming a lower electrode, a layer of dielectric material, and a via opening extending through the layer of dielectric material such that a top segment of the lower electrode is exposed below the via opening; Depositing a heater lining layer within a fraction of the volume of the via opening and over the layer of dielectric material; vertically recessing a horizontally extending portion of the heater lining layer; Depositing a phase-change material layer comprising a phase-change material and an upper electrode material layer over the horizontally extending portion of the heater lining layer; and Structuring the upper electrode material layer, the phase-change material layer, and the heater lining layer into a layer stack comprising a heater lining, a phase-change material portion, and an upper electrode.
Procedure according to Claim 11 , further comprising forming a tubular dielectric spacer in a marginal region of the via opening such that a central section of the top segment is exposed under a vacancy surrounded laterally by the tubular dielectric spacer, wherein the fraction of the volume of the via opening comprises a volume of a vacancy within the tubular dielectric spacer.
Procedure according to Claim 11 or 12 , wherein the vertical recession of the horizontally extending section of the heating lining layer includes performing a back-etching process that etches a material of the heating lining layer.
Procedure according to one of the Claims 11 until 13 , wherein a vertically extending seam is formed within a vertically extending section of the heating lining layer that is deposited within the fraction of the volume of the via opening.
Procedure according to Claim 14 , wherein: the heating lining layer is formed with a planar horizontal surface segment lying above the layer of dielectric material and an annular convex surface segment bordering a circumferential edge of an opening in the planar horizontal surface segment and comprising a lower apex bordering an upper end of the vertically extending seam; and the vertical recession of the horizontally extending portion of the heating lining layer comprises performing a back-etching process which simultaneously vertically recesses the annular convex surface segment of the heating lining layer while vertically recessing the horizontally extending portion of the heating lining layer.
Device structure comprising: a tubular dielectric spacer located within a via opening in a layer of dielectric material; a heater liner comprising a vertically extending section laterally surrounded by the tubular dielectric spacer and a horizontally extending section that lies above a top-side segment of the layer of dielectric material; a phase-change material section comprising a phase-change material contacting a top-side of the heater liner; and a top electrode contacting a top-side of the phase-change material section.
Device structure according to Claim 16 , wherein: the heating lining comprises a planar horizontal surface segment that lies above the layer of dielectric material, and further comprises an annular convex surface segment that borders a circumferential edge of an opening in the planar horizontal surface segment and lies above the via opening; and the phase-change material section contacts the annular convex surface segment.
Device structure according to Claim 16 or 17 , wherein: the vertically extending section of the heating lining comprises a vertically extending seam; and an upper surface of the heating lining comprises an annular convex surface segment having a lower apex adjacent to an upper end of the vertically extending seam.
Device structure according to one of the Claims 16 until 18 , wherein: the phase change material section comprises a vertically extending section located within a central region of the via opening; and the vertically extending section of the heater lining comprises a cylindrical inner wall contacting the vertically extending section of the phase change material section.
Device structure according to one of the Claims 16 until 19 , further comprising at least one sidewall lining located on at least one sidewall of the phase change material section, contacting a sidewall of the horizontally extending section of the heating lining, and comprising a material with an electrical conductivity higher than an electrical conductivity of an amorphous phase of the phase change material.

Description

RELATED REGISTRATIONS This application claims priority of the provisional US Application No. 63/711,791 entitled “Phase Change Memory Device and Methods for Manufacturing the Same”, which was submitted on October 25, 2024, and the entire contents of which are hereby incorporated into the present text by reference for all purposes. BACKGROUND Phase change material (PCM) devices can be used for memory-based computing applications due to their scalability and non-volatility. However, the manufacturing process sequence for PCM devices requires many processing steps. One of the time-consuming and costly processing steps involves the formation of bottom electrodes and heating elements using a chemical-mechanical polishing process. BRIEF DESCRIPTION OF THE DRAWINGS Aspects of this disclosure are best understood with reference to the following detailed description, when read in conjunction with the accompanying figures. It should be noted that, in accordance with common industry practice, various structural elements are not drawn to scale. The dimensions of the various structural elements may be enlarged or reduced as necessary for the sake of clarity in this discussion. 1 is a vertical cross-sectional view of an intermediate structure of a first embodiment after the formation of field-effect transistors, metal interconnect structures and layers of dielectric material according to an embodiment of the present disclosure. 2 is a vertical cross-sectional view of the intermediate structure of the first embodiment after the formation of via openings through a layer of dielectric material according to an embodiment of the present disclosure. 3 is a vertical cross-sectional view of the intermediate structure of the first embodiment after the formation of a layer of dielectric spacer material according to an embodiment of the present disclosure. 4 is a vertical cross-sectional view of the intermediate structure of the first embodiment after the formation of tubular dielectric spacers according to an embodiment of the present disclosure. 5 is a vertical cross-sectional view of the intermediate structure of the first embodiment after the formation of a continuous layer stack comprising a heating lining layer, a phase change material layer and a material layer for the upper electrode according to an embodiment of the present disclosure. 6 is a vertical cross-sectional view of the intermediate structure of the first embodiment after structuring the continuous layer stack to layer stacks in progress, each comprising a heating lining in progress, a phase change material section in progress and an upper electrode in progress according to an embodiment of the present disclosure. 7 is a vertical cross-sectional view of the intermediate structure of the first embodiment after the formation of a sidewall lining layer according to an embodiment of the present disclosure. 8 is a vertical cross-sectional view of the intermediate structure of the first embodiment after the formation of side wall linings in progress according to an embodiment of the present disclosure. 9 is a vertical cross-sectional view of the intermediate structure of the first embodiment after structuring the layer stacks under construction into layer stacks, each comprising a heating lining, a phase change material section and an upper electrode, and structuring the side wall linings under construction into side wall linings according to an embodiment of the present disclosure. 10 is a vertical cross-sectional view of the structure of the first embodiment after removal of a structured etching mask layer according to an embodiment of the present disclosure. 11A - 11C Illustrating successive top views of a region of a first device of the structure of the first embodiment during the processing steps of 8 - 10 . 12A - 12C Illustrating successive top views of a region of a second device of the structure of the embodiment during the processing steps of 8 - 10 . 13A - 13C Illustrating successive top views of a region of a third device of the structure of the embodiment during the processing steps of 8 - 10 . 14 illustrates a top view of a region of a fourth device of the structure of the embodiment after the processing steps of 8 . 15 is a vertical cross-sectional view of the structure of the first embodiment after the formation of a dielectric encapsulation layer and additional metal interconnect structures according to an embodiment of the present disclosure. 16A - 16D are various arrangements of a phase-change memory cell in different programmed resistance states according to an embodiment of the present disclosure. 17 is a vertical cross-sectional view of an intermediate structure of a second embodiment after the deposition of a heating lining layer according to an embodiment of the present disclosure. 18 is a vertical cross-sectional view of the intermediate structure of the second embodiment after the vertical recession of the heating lining layer according to an emb